Sodium Intake and Its Associated Factors

Anggi L. Wicaksana, RN, MSc

Department of Medical Surgical Nursing,

School of Nursing, Faculty of Medicine Universitas Gadjah Mada

Gd. Ismangoen 2F Jl. Farmako, Sekip Utara Fakultas Kedokteran UGM

Correspondence: anggi.l.wicaksana@ugm.ac.id

 

Sodium Intake

Understanding Sodium Intake

Sodium intake defines as whole ingestion food-contained sodium in daily diet practice (WHO, 2012, 2013). Almost all foods we consumed are having sodium, from natural sources or by adding sodium while cooking/processing a food. In human body, sodium substance is required in order to maintain plasma volume, acid-based balance, nerve impulse transmission, normal cell function and almost it has function related to maintenance fluid balance (WHO, 2012). Since 95% sodium intake is excreted through urinary, 24 hours urinary collection become gold standard in measuring sodium intake (24h UNa). For several countries this approach could be difficult to apply then sodium intake will be measured using 24-hour dietary recall, food diaries, food frequency questionnaire or converting food-contained sodium into the amount of sodium inside. Recently, the researcher develop instrument to measure sodium intake such as scored sodium questionnaire and salt intake questionnaire but it most appropriate for local community because every area has different type of sodium sources (Batcagan-Abueg et al., 2013; Charlton et al., 2008; Elliott & Brown, 2007; Mason et al., 2014; WHO, 2013). Measuring sodium intake becomes important part to assist future planning and decision making related to intervention on hypertension.

Sodium restriction has been well known to be effective approach to prevent and control hypertension. Daily sodium consumption suggested for patients with hypertension is no more than 2 grams consisting whole ingested foods (WHO, 2012, 2016). In fact, it is challenging to have low sodium consumption particularly for patients with hypertension. Some studies have released the major reason sodium restriction are difficulty to prepared and separated foods contain low sodium, inadequate knowledge or information, low motivation and awareness, failure to maintain the low sodium diet (Cornélio et al., 2009; de Brito-Ashurst et al., 2013; Kamran et al., 2014; Lennie et al., 2008; Neily et al., 2002; Qin et al., 2014; Srikan & Phillips, 2012; Welsh et al., 2013). Those reasons make patients fail to undergo low sodium diet and be trapped in high sodium-food intake.

Many studies concerned on sodium intake, found sodium consumption above the physiological need (Batcagan-Abueg et al., 2013; WHO, 2012). Study of sodium intake around the world tells sodium consumption for general population was between 1.56 g/day and 10.6 g/day. The INTERSALT study reveals country which has highest sodium intake was China, Republic of South Korea and Japan respectively. In China the average sodium consumption is 5.95 g/day for male and 5.35 g/day for female until almost 12 g/day sodium that comes from adding salt while cooking process (Bentley et al., 2009; J. Chen et al., 2013; Cornélio et al., 2009; Elliott & Brown, 2007; Kamran et al., 2014; Powles et al., 2013; Qin et al., 2014; Welsh et al., 2013; WHO, 2012). This condition indicates that Asian people have high risk in consuming high sodium-foods. Sodium intake also depends on source of sodium, which is consumed because different place has different source of sodium. As previous study, people in western countries prefer to consume high sodium-food from processed food or food outside-their home meanwhile Asian people favor to add sodium when they cook. This situation is influenced by culture and available natural resources (Anderson et al., 2010; Batcagan-Abueg et al., 2013; J. Chen et al., 2013; Elliott & Brown, 2007; Hin & Khor, 2011; Papadakis et al., 2010). Study in Thailand has interesting finding. In the Thai urban area, people love consumes processed foods while adding salt on home cooked-foods is common in Thai rural area (Srikan & Phillips, 2012). This finding indicates there is transformation related source of sodium. In addition, this idea should become the main concern when designing intervention program related to sodium intake or sodium restriction in order to create appropriate and effective program.

Inappropriate program of sodium intake will lead high sodium consumption, which in turn has effect on blood pressure. High sodium in the body will stimulate increasing serum osmolality then induces osmotic stimulus. This stimulation will appear as thirsty and encourage patients to take more fluid. High consumption of fluid can impact the heart by increasing heart beat and pumping. For the blood vessel, high fluid inside body will make over load and have peripheral systemic resistance. On the other hands, ion sodium will have bonding and tend to make fluid retention because high sodium will ruin fluid balance and osmolality. Fluid retention combines with extra heart pumping can lead raised blood pressure and it will provoke the worst condition of hypertension (Adrogué & Madias, 2007; Welch et al., 2006). Finally, excessive sodium intake has direct associated with severe arterial hypertension, ventricular hypertrophy, stroke, renal stone and subsequence risk of cardiovascular diseases (Batcagan-Abueg et al., 2013; Cornélio et al., 2009; Kamran et al., 2014; Nerbass et al., 2014; Papadakis et al., 2010; WHO, 2012). Outstandingly, if the patients consume low sodium, it can decrease systolic blood pressure (SBP) 10.21 mmHg and 2.60 mmHg for diastolic blood pressure (DBP), which in turn potentially drops the prevalence of hypertension (Batcagan-Abueg et al., 2013; Kamran et al., 2014; Papadakis et al., 2010; Sacks et al., 2001). In addition sodium restriction can decrease mortality and incidence of cardiac artery diseases by maintaining heart condition and managing fluid inside human body (Qin et al., 2014; Srikan & Phillips, 2012).

 

Factor Associated Sodium Intake

Factors that already known have association with sodium intake consist of age, gender, educational level, ethnicity, religion, monthly income, marital status, central obesity and co-morbid condition.

a. Age

Sodium intake is influenced by patient’s age. Previous study had been released that younger people consumed more salty foods, come up from sodium in urinary sodium excretion. Kamran et al. (2014) identified that middle-aged patient (30–40 year-old) consumed high sodium intake and had significant difference compared with other sub-ages. Similar finding also can be found in research conducted by Nerbass et al. (2014). It had been established that younger patient consumed high sodium in their daily dietary practice and become independent determinant of high sodium intake. Understandable, younger people mostly eat any kind of foods and no have good control on their diet. It will be different on old people who have consideration to control their sodium because they have awareness related their health condition (Hin & Khor, 2011; Kamran et al., 2014; Nerbass et al., 2014).  This finding gives us the idea that we have to more concern on middle-aged and younger patients because they have tendency on high sodium consumption. This does not mean that we can ignore other sub-ages however we have to more aware that the middle aged group and younger patients have risk in high sodium intake.  

b. Gender

Identification of sodium consumption among gender had been conducted. It has different finding regarding the influence of gender on sodium consumption. Kamran, et al. (2014) found that female has high sodium intake on their daily practice. This finding was founded because of cultural paradox and nutritional pattern in Iranian women that commonly consume high sodium. On the other hands, other studies found female has higher adherence of sodium restriction compared with male which in turn they had low sodium excretion on 24h UNa. Female has more knowledge and self-care than male and the effect of sodium restriction program had greater impact on female (Chung et al., 2006; Sacks et al., 2001). This finding also was strengthened that male consumed high sodium-foods 10% higher than female (Powles et al., 2013). Further study also emphasized that being a male was independent variable of high sodium–food intake (Nerbass et al., 2014). It has been known that female have more concern on their health condition and lead them adhere on sodium restriction program that finally they have low sodium intake. Otherwise, male patients was less concern in their sodium restriction, which make they have high sodium intake.

c. Educational Level

Educational level influences how easy people receive health information. It had been noticed that higher education would make people easy in receiving health education. Nerbass et al. (2014) found the interesting finding on the effect of educational level on sodium intake. It was found that patients who had higher education had high sodium consumption in their daily dietary practice. After having deep exploration, Nerbass et al. (2014) concluded that it happened because many respondents recruited were male and young people, other variables that also influence sodium intake. Another study discovered that uncontrolled hypertension patients who had basic (lower) education have significant difference of sodium intake compared with controlled hypertension group (Kamran et al., 2014). The lower level of education patients who had uncontrolled hypertension mostly they love to eat high sodium foods. It looks like the lower education also has correlation to sodium intake even though it should take a look for further research, whether they have controlled or uncontrolled hypertension.  

d. Ethnicity

Dietary practice, involved sodium consumption, depends on cultural preference and available natural resources. This condition makes different dietary practice among different ethnics in the world. Previous study about ethnicity and sodium intake revealed African American had high sodium consumption on their daily diet. This situation has happened since the slavery era while many African Americans came and ate any kinds of salty and fatty foods. It became their dietary pattern and habit, eating salty and fatty foods then it induced obesity among this group (Chung et al., 2006; D. James, 2004). Additionally, Sacks et al. (2001) found the sodium restriction program had greater impact on black people; another evidence also revealed that African American has risk in high sodium intake. Recent study finds other findings. Study on South Asian people revealed Asian people consume high sodium food in daily diet (Batcagan-Abueg et al., 2013). INTERSALT study of sodium intake around the world denoted that China, Republic of South Korea and Japan were the top three countries, which consume high sodium. At least, daily sodium consumption on Asian people is 4.6 gram/day, higher than WHO recommendation on dietary sodium intake (Elliott & Brown, 2007). Current data on sodium intake around the world also emphasized that Asian countries have high risk in taking salty foods and being the top list of higher sodium consumption particularly for East Asia and Central Asia (Powles et al., 2013). This finding indicates that Asian people have risk in high sodium intake more than other countries and ethnicities.

e. Religion

Religion gives the detail law in dietary practice (Hye-Cheon Kim, Alex Mcintosh, Kubena, & Sobal, 2008). All believers will consume foods by considering dietary rules in order to obey God. It is not clearly known religion correlate with sodium intake, however religion can affect believers’ eating behavior, including sodium intake (Hye-Cheon Kim et al., 2008). The majority of population in Indonesia is Muslim and only “Halal Food” that can be eaten by Muslim people as religious law (Hossain, 2014). Besides the halal foods, there is forbidden foods (Haram Foods), to be consumed by Muslim people e.g. pork, lard or any porcine substance, alcohol, meat that is not slaughtered in the prescribed Islamic way etc. Additionally for Muslim, there is a guidance to avoid harmful foods that can bring negative effect on health in daily dietary practice (Hossain, 2014). For instance, it is recommended to avoid too salty, sweetie, spicy and unhealthy foods besides the firmed forbidden foods (Hossain, 2014). This concept might have idea that there is correlation between religion and sodium intake. Knowing this information will have benefit especially for Muslim majority countries such as Indonesia.

f. Annual Income

Family consumption is determined by family income. Low-income family will consume bad quality foods including salty and fatty foods. This socioeconomic issue had been published as one of risk factors leading to unhealthy behavioral risk factors (WHO, 2016). Interestingly, study in UK released there was no significant association between low-income family and high sodium intake. However, it had been identified that low-income family consumed and purchased high sodium food in their dietary practice (Nerbass et al., 2014). Other studies also had similar finding, there was no association between income and sodium intake. In fact, further exploration found there was significant difference between controlled and uncontrolled hypertension on low-income family regarding their sodium intake. The uncontrolled hypertension on low-income group had showed as factor that could influence sodium intake (Kamran et al., 2014). Further, Welsh, et al (2013) tried to explore the income perception toward adequacy to meet the family need and low sodium intake. However, the result also revealed there was no significant association on income perception and sodium intake. The understanding of this finding probably needs other study to explore and explain evidently.

g. Marital Status

Marital status also could influences the sodium intake. Previous study reported that there is no significant correlation between marital status and sodium consumption (Kollipara et al., 2008; Welsh et al., 2013). It is believed, patients who have married will consume their sodium intake from homemade foods. Additionally, patients who have already married will have relative to control and reminder about their sodium ingestion. Probably, this association of marital status and sodium intake need further explanation and knowledge.

h. Central Obesity

Obesity that located on abdominal region is known as central obesity. To get the central obesity, Waist-Hip Ratio (WHR) is used to determine fat accumulation in the body (WHO, 2008). Previous study indicated that there was a correlation between central obesity and high sodium intake. Nerbass et al. (2014) found that central obesity became independent variable influencing high sodium-food intake. It is known that obesity people love to consume high caloric foods and accumulate as body fat in abdominal area. Additionally they also frequently ingest high sodium foods, seasoning source or other junk foods. In other research, obesity people tend to consume high calorie foods accompanied by sugar-sweetened soft drink. Most of those products consist of high sodium as preservative substance. Another study also proposed salty enriched-foods has direct association with obesity. So, it is rational when central obesity patients like to eat high sodium intake in their dietary practice, which is manifested as higher score of WHR.

i. Co-morbid Condition

Daily sodium intake is also defined and correlated with co-morbid condition. As recorded, diabetes patients have association with high sodium food intake. Patients with diabetes sometime forget about their prescribed diet. Then, they break the rule and consume any foods, involve high sodium foods intake. Nerbass et al., (2014) emphasized that diabetes as one of the independent variable, which associated with high sodium intake. Another co-morbid condition that can influence high sodium intake is current/previous smoking. The result denoted that person who has current or previous smoking tends to consume high sodium-food intake. Smoking persons tend to have no regular pattern in healthy eating because they most enjoy smoke rather than eat. For other co-morbid condition such as having heart failure, stroke/CVA, chronic kidney diseases etc. still have no evidence to support. Most of these co-morbid conditions are complication of hypertension and most of them are prescribed to restrict sodium consumption (Cornélio et al., 2009; Kamran et al., 2014; Nerbass et al., 2014; WHO, 2012). Thus it also can affect the sodium intake.

 

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